1 Field of the Invention
The present invention relates to a safety valve assembly for use in a closed fluid system, such as an air or hydraulic braking system. More particularly, the safety valve assembly provides a means by which a fluid line which is defective, causing a loss of pressure, may be effectively isolated from the system to maintain pressure within the remainder of the closed system.
2 Description of the Prior Art
Heretofore, various safety devices have been proposed for use in a closed fluid system, for controlling loss of pressure within same, when a portion of the system becomes defective.
All such previously proposed devices have notably included some sort of piston which is spring biased against a positive pressure such that, when pressure drops significantly, the piston is moved against the discharge end of the device by the spring to isolate the downstream section or branch of the system, allowing the remainder of the system to maintain pressurinzation, and thus function.
Examples of such previously proposed devices are to be found in: Owens U.S. Pat. No. 2,625,951; Berglund U.S. Pat. No. 3,109,448; Reese U.S. Pat. No. 3,141,302; Smith U.S. Pat. No. 3,325,996; Berglund U.S. Pat. No. 3,408,119 and 3,439,704; Nunez U.S. Pat. No. 3,506,977; and Kobashi U.S. Pat. No. 3,759,288.
The safety valve assembly of the present invention, as will be defined in greater detail hereinafter, differs from the devices previously proposed by relying on differential fluid pressure for actuation and deactuation and wherein spring means for biasing structure within the assembly are notably absent.